An Alternative Approach Based on Skin Electrical Impedance to Determine Transepidermal Water Loss for Skin Barrier Function Assessments

Abstract

Purpose: The transepidermal water loss (TEWL) has long been measured as an indicator to assess the skin barrier function in dermatological research and clinical practice. However, practical limitations such as time requirement, environmental sensitivity, and measurement complexity hinder the widespread uptake of conventional TEWL measurements in clinical settings and routine monitoring. Consequently, there is a growing need for rapid, robust, and clinically applicable alternatives to conventional TEWL measurements. Here, we present a simple, non-invasive, and time-efficient method based on the skin electrical impedance for skin barrier function assessments. Methods: The skin electrical impedance, TEWL, stratum corneum (SC) thickness, and SC surface water content of 25 healthy adult participants with no history of dermatological diseases were measured at two adjacent forearm sites: intact site with a normal skin barrier and tape-stripped site with an impaired skin barrier. The measured impedance was used to calculate the SC thickness and surface water content, from which the TEWL was estimated and then compared against the TEWL measured using a Tewameter. The estimation accuracy was evaluated by determining the correlation coefficient (R) and root mean square error (RMSE) between estimated and measured TEWL. Results: A strong correlation (R = 0.891) was observed between estimated and measured TEWL, with an RMSE of 6.05 g/m²/h, indicating high accuracy of the proposed method. Conclusion: This impedance-based method provides accurate estimations of the TEWL, indicating its potential as a practical alternative to conventional TEWL measurements for skin barrier function assessments, particularly in clinical or high-throughput settings.